Automatic draft regulation



Jully 24, 1934. M. J. BREDE I 1,967,494

AUTQMATIC bRAFT REGULATION Filed July 20, 1951 INKENTOR.

Patented July 24, 1934 PATENT OFFICE AUTOMATIC DRAFT REGULATION Martin J. Brede, Oakland, Calif., assignor, by

mesne assignments, to Walter M. Dunphy, Sacramento, Calif.

Application July 20, 1931, Serial No. 551,834

2 Claims.

This invention is an automatic draft regulator and is specially directed to the regulation of draft under boilers.

The main object of the invention is to provide means for automatically regulating furnace draft for highest efliciency, and maintain uniformity in heating and efficiency during the entire period of boiler operation.

Another object of the invention is to provide such means whereby automatic draft regulation is obtained during firing periods, water injection, and during normal operation of the boilers.

A further object of the invention is to provide such automatic means with adjusting means to suit the particular requirements and installation of boilers and stack or fiue.

Further objects and advantages of the invention will become apparent as the following description is read on the drawing forming a part of this specification and in which similar reference characters are used to designate similar parts throughout the several views, and in which;

Fig. 1 is a side elevation of the invention as applied to the breeching of a bank of boilers.

Fig. 2 is a front elevation of Fig. 1.

Fig. 3 is a side elevation of a gravity operated modification of the invention.

Fig. 4 is a front elevation of Fig. 3.

Fig. 5 is a section taken on line 5-5 of Fig. 2.

Fig. 6 is a sectional elevation of the hinge pivots.

The invention may be applied to the breeching 10 of a bank of boilers, to the stack, or other part of the draft system as occasion may require.

The invention consists of an air valve automatically actuated by the draft in the flue, and as indicated in the drawing consists of a housing 11 having flanges 12 riveted to the breeching 10. The outer end of housing 11 is inwardly flanged as at 13 to form a frame for a door or closure 14.

The door 14 closes against the inside of flanges 13 and consists of a flat plate, one side 15 of which is formed about a shaft 16 and secured thereto. A conical seat 17 is formed in each end of the shaft. A conically pointed screw 18 is adjustably secured in the top and bottom walls "of housing 11 and cooperates with the conical seats 17 permitting convenient removal and replacement of the door.

Counterbalancing means is provided and preferably consists of a bar 19 secured to door 14 and having a spring 20 cooperating therewith, the spring being adjustable as to tension as indicated at 21, consisting of a screw threaded bolt 22 secured in spring 20 and cooperating with a bracket 23.

A modification of the invention is shown in Figs. 3 and 4 which is adapted to weight counterbalancing, the housing being angularly mounted on the breeching 10. The construction is similar to that of Figs. 1 and 2 except as to the angular mounting and weight counterbalance.

The weight counterbalance consists of an arm 24 secured to door 14 and having a slot 25 in which a bolt 26 is slidably adjustable, a weight 27 being secured in adjusted position by the bolt 26.

The operation of the invention is as follows:

The spring 20 is adjusted to the desired tension as derived from actual experiment after installation of the device, or the weight 27 is adjusted to the correct position on the arm 24, the door being normally closed and having a slight resistance to opening. 5

When the fires are started, the door remains closed. When the heat is suflicient to create excess draft, the draft in the flue draws the door partly open, depending on the pressure created by the draft. Opening the fire door or firing causes a drop in temperature and consequently in pressure, which permits the door to close in amount relative to the decrease in temperature and consequent pressure.

It will be noted that by this method, practical uniformity in draft and operation is obtained.

It will also be noted that variations in construction and arrangement of parts which are consistent with the appended claims may be resorted to without detracting from the spiritor scope of the invention or sacrificing any of the advantages thereof.

I claim:

1. An automatic draft regulator comprising an independent housing adapted to be attached to and extend outwardly from the breeching of a furnace and communicate therewith, the outer end of the housing having a door opening positioned in downwardly converging and acute angular relation to a vertical plane, a door hinged along one side edge of the opening, the door being weighted whereby under normal atmospheric conditions it will be positively held' by gravity in closed position over the door opening.

2. A structure as in claim 1 with means to adjust such weight whereby the resistance to the opening of said door by induced drafts in the breeching may be varied.

MARTIN J. BREDE. 

